1. Field of the Invention
The present invention relates to methods for allocating resources in a virtual desktop environment.
2. Description of the Related Art
The computing industry has seen many advances in recent years, and such advances have produced a multitude of products and services. Computing systems have also seen many changes, including their virtualization. Virtualization of computer resources generally involves the abstraction of computer hardware, which essentially isolates operating systems and applications from underlying hardware. Hardware is therefore shared among multiple operating systems and applications each isolated in corresponding virtual machines. The result of virtualization is that hardware is more efficiently utilized and leveraged, and resource management in a distributed environment like Virtual Desktop Infrastructure (VDI) is becoming a more promising solution. With VDI, users access over a network connection personal desktops provided by virtual machines running on remote servers. Each VM is a complete execution environment, and the server provides a user interface over the network connection so that user inputs and outputs are communicated between the user and the VM. It is desirable to provide a desktop experience to the end-user when using remote services similar to the experience users have when using a traditional system where programs execute locally. The quality of the user experience can vary based on many underlying factors such as round-trip latency or network bandwidth.
A virtual machine executing on a computer system will typically be limited to the resources (such as memory space, CPU cycles, network bandwidth, and so on) of that computer system. The virtual machines executing on a first computer system typically share the resources of the first computer system. The virtual machines executing on a second computer system typically share the resources of the second computer system. The performance of a virtual machine will depend on the resources of the computer system on which the VM is executing, as well as the demands of any other virtual machines executing on the same computer system. This “single” platform represents an undesirable limitation in some situations.
Virtual machines are assigned to computer systems in a manner that balances the loads of the virtual machines among the various computer systems. Processes, such as virtual machines, are known to be balanced based on allocation policies, resource demand, and the availability of resources provided by computer systems. Balancing can be applied to computer resources such as processor time, i.e., CPU cycles, memory space, network bandwidth (including any type of input/output or bus bandwidth), storage space, power consumption, cache space, software licenses, and so on. To effectively balance the computing resources, some systems implement a “migration” of a running virtual machine (VM) from one system to another.